Lateral rectangular (R-) and step-like (S-) channel phase-change memory (PCM) cell structures are numerically analyzed for multi-state storage based on their temperature distributions and their programming characteristics. The S-PCM cell is characterized by the sequentially melted sub-channel and step-like programming characteristics. From the viewpoint of the performance for multi-state storage, the step-like characteristics indicate high controllability for its application of multi-state storage.